This invention relates to a gun assembly and to projectiles of a non-lethal type, for example for use in riot control situations.
The need for projectiles that can be fired from guns with a reduced risk of lethal impact upon a human frame is well documented. Thus, baton rounds, or plastic bullets as they are commonly known, have long been used in civil disorder situations such as riots. The intention behind such baton rounds is to inflict pain and discomfort on rioters, thereby halting and/or deterring further rioting, but without causing serious injury to any person struck by the baton round.
However, the projectiles that have been developed and are currently used by police and military forces have been found to suffer from a number of significant problems. In particular, it has been found that current projectiles:
(a) cause serious injury when used incorrectly;
(b) are inaccurate;
(c) are expensive for training; and
(d) cause secondary injuries from sharp edges and ricochets.
It is an object of the present invention to overcome the aforementioned problems.
Accordingly, in a first aspect, the invention provides a combination of a gun having a barrel; propellant means for launching a projectile from the barrel; and a non-lethal projectile;
characterised in that the non-lethal projectile comprises a hollow outer casing formed from a resiliently deformable material, and a plurality of balls within the casing, the outer casing being deformed as it travels along the gun barrel under pressure from the propellant means but being sufficiently resilient to resile to a substantially undeformed state upon leaving the gun barrel.
In a further aspect, the invention provides a projectile for use in a gun as hereinbefore defined, the projectile comprising a hollow outer casing formed from a resiliently deformable material, the outer casing containing a plurality of balls, the outer casing being deformable as it travels along the gun barrel under pressure from the propellant means but being sufficiently resilient to resile to a substantially undeformed state upon leaving the gun barrel.
In a still further aspect, the invention provides a projectile comprising a hollow outer casing formed from a resiliently deformable material, the outer casing containing a plurality of balls, the outer casing being deformable when contacted by propulsion means but being sufficiently resilient to resile to a substantially undeformed state in flight.
Preferably, lubrication means are provided for reducing friction between the outer casing and the barrel as the projectile travels along the barrel.
It is important that the projectile is shaped so as to be free of any sharp edges and protrusions that might cause injury and hence preferably the outer casing of the projectile is spherical. As an alternative, for example with smaller projectiles, it could have a teardrop shape. The spherical shape of the outer casing also has good ballistic characteristics allowing good accuracy to be achieved.
Similarly, the balls within the casing are free from sharp edges and most preferably are of substantially spherical form. The surfaces of the balls are smooth so as to allow one ball to slide readily over the surface of another. This is important because the ability of the balls to be redistributed in the outer casing rapidly upon impact with a target will determine the extent to which the energy of impact of the bullet is absorbed by the projectile rather than the target.
The outer casing is resiliently deformable and, when the gun is fired, the outer casing deforms under the pressure of the propellant means, but the shape of the projectile ensures that the center of mass of the deformed projectile remains centered on the axis of the gun barrel. The projectile is sufficiently resilient to enable it to regain a substantially spherical shape upon exit from the gun barrel thereby ensuring greater accuracy.
The outer casing is preferably formed from an elastomeric material, for example a natural or synthetic rubber. The elastomeric material typically has a Shore hardness in the range from 40 to 80, more typically in the range from 45 to 55.
The balls within the outer casing typically have a maximum dimension (e.g. diameter) in the range from 2 mm to 10 mm, preferably from 2.5 mm to 6 mm. The number of balls within the outer casing will vary according to the size of the balls and the overall size and weight of the projectile but, for example, the casing can contain from 150 to 250 balls.
The balls are usually formed from a material having a density greater than the resiliently deformable material from which the outer casing is formed. In general, the minimum density of the balls is equivalent to a specific gravity of 7.0. For example, the balls can be formed from a metal such as steel. In one embodiment, the balls can take the form of steel ball bearings, although it is not necessary for the balls to have same polished surface finish as ball bearings.
The balls are relatively hard compared to the outer casing and typically the minimum hardness of the balls is 106 Brunel Units which corresponds to a Rockwell hardness of 90.5. Thus, the balls should preferably have a hardness at least as great as mild steel. It has been found that when the balls are made of a softer metal such as lead or brass, the balls have a tendency to fuse together upon impact, which could have potentially lethal results.
The overall weight of the projectile, including the casing and the balls, is usually in the range from 60 to 150 grammes, for example from 75 to 125 grammes.
The casing is made from a material which is sufficiently tough and thick to ensure that it does not rupture during firing or during normal impact on a target. Thus, for example, the outer casing typically has a thickness in the range from 2 mm to 8 mm, more usually 3 mm to 5 mm.
In another aspect, the invention provides a cartridge comprising a cartridge casing, a propellant and a projectile as hereinbefore defined.
In a particular embodiment, the cartridge casing can contain a piston which is slidably disposed in the cartridge casing behind the projectile so as to eject the projectile therefrom when the gun is fired.
The cartridge casing preferably contains means (e.g. lubrication means) for reducing friction between the outer casing of the projectile and the barrel as the projectile travels along the barrel.
The projectile is preferably disposed within a cylindrical sleeve forwardly of the piston, the cylindrical sleeve being formed from a low friction material and being arranged to be ejected from the gun barrel with the piston and projectile when the gun is fired, the projectile becoming separated from the sleeve after emergence from the gun barrel.
The sleeve can be formed from, for example, a paper or a low friction material such as PTFE.
The sleeve serves to prevent the projectile from coming into contact with the cartridge case or the barrel, at least for a substantial proportion of the distance of travel of the projectile down the gun barrel. The sleeve provides a low and relatively constant friction level between the projectile and the gun barrel and prevents any drag that might otherwise arise from a relatively high friction material such as a rubber. Alternatively, however, the outer casing of the projectile can be formed from a relatively low friction material (e.g. PTFE), or can be treated with a friction reducing substance such as PTFE.